Close split of sorghum and maize genome progenitors
Close split of sorghum and maize genome progenitors
复制标题
DOI：
10.1101/gr.2332504
复制
发表时间：
2004-10-01
期刊：
影响因子：
7
通讯作者：
Messing, J
中科院分区：
文献类型：
--
作者：
Swigonov치, Z;Lai, JS;Messing, J
人们普遍认为玉米（Zea mays L.）SSP. mays）作为四倍体出现;然而，这两个祖先基因组不能在现代玉米的基因组中明确地追踪。我们已经采取了一种新的方法来研究玉米基因组的起源。我们从玉米基因组的五个重复位点及其高粱中的直向同源位点周围的区域分离并测序了大的基因组片段，然后将这些序列与水稻基因组中的直向同源区域进行了比较。在所研究的片段中，我们确定了11个在位置、顺序和方向上保守的基因。我们进行了系统发育和距离分析，并检查模式的估计时间的分歧高粱和玉米基因的直系同源物，也分歧玉米直系同源物的时间。我们的研究结果支持玉米的四倍体起源。这项分析还表明，大约1190万年前（Mya），祖先高粱基因组和两个玉米祖先基因组同时出现分歧。基于一个推定的转换事件检测的基因之一，四倍化必须在4.8 Mya之前，因此，之前的主要玉米基因组扩增的基因扩增和反转录转座。
It is generally believed that maize (Zea mays L. ssp. mays) arose as a tetraploid; however, the two progenitor genomes cannot be unequivocally traced within the genome of modern maize. We have taken a new approach to investigate the origin of the maize genome. We isolated and sequenced large genomic fragments from the regions surrounding five duplicated loci from the maize genome and their orthologous loci in sorghum, and then we compared these sequences with the orthologous regions in the rice genome. Within the studied segments, we identified 11 genes that were conserved in location, order, and orientation. We performed phylogenetic and distance analyses and examined the patterns of estimated times of divergence for sorghum and maize gene orthologs and also the time of divergence for maize orthologs. Our results support a tetraploid origin of maize. This analysis also indicates contemporaneous divergence of the ancestral sorghum genome and the two maize progenitor genomes about 11.9 million years ago (Mya). On the basis of a putative conversion event detected for one of the genes, tetraploidization must have Occurred before 4.8 Mya, and therefore, preceded the major maize genome expansion by gene amplification and retrotransposition.